1. Field of the Invention
The invention relates to a valve apparatus which may be utilized in a fluid transmission conduit of a subterranean well to isolate fluid flow passing therethrough.
2. Description of the Prior Art
It frequently is necessary to isolate flow of fluids within a fluid transmission conduit, such as a tubing string in a subterranean well. The prior art is familiar with many varied designs of valves, particularly "safety" valves that utilize a ball having a flow passageway therethrough as the valve head. Such valves have been found to be particularly reliable in subterranean well applications.
Ball valves have a camway slot defined on the exterior thereon for receipt of a ball or bearing element therein which is secured to the valve seat or other means have been utilized to pivot the ball relative to the seat of the valve in response to hydraulic activation and incorporation of piston means. Oftentimes, it is desirable to provide a ball valve apparatus which is not responsive to hydraulic activation, but which is directly responsive to mechanical manipulation of the fluid transmission conduit, such that, for example, the valve may be activated before and/or after the setting or release of another tool, such as a packer, bridge plug, or the like.
The present invention provides a valve apparatus which comprises such a valve head and seat configuration, but which is responsive to fluid conduit mechanical manipulation to activate the valve and shift it between open and closed positions.